Diffuser tube



April 25, 1967 R. J. KLINGBEIL ETAL. 3,315,895

DIFFUSER TUBE Filed Feb. 5, 1965 United States Patent O 3,315,895 DIFFUSER TUBE Raymond J. Klingbeil and Albert E. Lang, Columbus, Ollio, assignors to FMC Corporation, a corporation of Delaware Filed Feb. 5, 1965, Ser. No. 430,634 4 Claims. (Cl. 239-145) This invention relates to a diffuser tube used for the aeration of liquid, or for the dispersion of gases or vapors therein, and more particularly to diffuser tubes of flexible, collapsible, fora-minated fabric into which the air or gas is supplied under pressure, and through the interstices of which the air or gas passes in fine bubbles into the liquid in which the diffuser tube is immersed. Any reference hereinafter to air will be understood to include gas or any other aeriform body.

Diffusers of the type `with which the present invention is concerned are employed in the activated sludge process of treating sewage, ore flotation processes, treatment of industrial wastes, various fermentation processes, and other chemical processes where gas-liquid contact is essential.

The diffuser tube of the present invention comprises a flexible, collapsible, porous sleeve having one open end secured to a rigid adapter fitting with a substantially airtight connection, and a rigid skeletal frame member within said sleeve and having one end rigidly secured to said adapter fitting. The sleeve and the frame member are of substantially the same length, and the sleeve has its other end permanently closed to completely enclose the frame member. The adapter fitting is connected to an air supply line that passes air through the fitting and into the sleeve at a pressure great enough to cause it to pass through the interstices of the fabric of which the sleeve is made.

The aeration apparatus includes a quick acting valve that is located in the air supply line so that the diffuser tube is vented to the atmosphere simultaneously with the closing of the air supply line. The venting of the diffuser tube to the atmosphere causes the sleeve to collapse quick-` ly upon shut off of the air pressure. The sleeve has enough slack, relative to the skeletal frame member enclosed therein, that portions of the fabric slap against each other, when the sleeve is collapsed, with sufficient force to dislodge the 'solid matter accumulated on the outer surface of the sleeve.

A structure by means of which the above mentioned and other advantages lof the invention may be attained will be described in the following specification, taken in conjunction with the accompanying drawings showing a preferred illustrative embodiment of the invention, in which: s

FIGURE 1 is a fragmentary elevational view of a diffuser tube embodying the invention, with a portion of the sleeve broken away to show other structure;

FIG. 2 is an enlarged cross sectional view, taken along the line 2 2' of FIG. 1;

FIG. 3 is a cross sectional view, taken generally along the line 3-3 of FIG. 1, and showing the sleeve in collapsed position; s

FIG. 4 is an enlarged cross sectional view of a portion of FIG. 3; and

FIG. 5 is a fragmentary elevational view, showing a modified form of sleeve.

In the drawings, a flexible, collapsible, porous sleeve 11 is made of flexible, porous, woven fabric, suitably of a plastic material. Thus it may be made from a synthetic linear polyamide such as nylon, from a copolymer of vinyl chloride and vinylidene chloride of the type known commercially as Saram from Orlon or other synthetic plastic material, from canvas or other suitable textile 3,3 15,895 Patented Apr. 25, 1967 material, from metal, or other suitable fabric strong enough to withstand the action of sewage and the pressure of the liquid in which it is immersed. The interstices in the fabric of the sleeve are small enough to cause the air or gas under pressure to pass through 'the fabric into the sewage, or other liquid in which the diffuser tube is immersed, in fine bubbles to lprovide optimum aeration or gasification of said liquid.

Sleeve 1'1 vmay be woven in the form of a continuous seamless tube and then cut into sections of desirable length to yform individual sleeves. It is preferred however, -for economical reasons, to sew the longitudinal edges of a flat sheet of the desired material together to form a tubular sleeve having a seam 12 on its inside. The longitu dinal edges of the flat sheet may be secured together in any suitable manner instead of sewing them. It is also possible to form a long tube by securing the longitudinal edges of a sheet together, and then cutting the tube into sections of the proper length. t

One end of the tubular sleeve is flattened and its edges se'wed together to provide apermanently closed end.

The closed end may be formed 'by clamping the edges together, or in some other manner, as, for example, by securing the edges of a circular piece of the fabric to the edges of the tubular sleeve at one end thereof. It is preferred to make the joint at the closed end of the sleeve substantially airtight so that the air passing from the sleeve into the sewage must pass through the interstices of the fabric of which the sleeve is made,

The open end 14 of sleeve 11 is secured to an adapter fitting 15 which may be cast or molded of any suitable material, such as, for example, iron, aluminum, phenol formaldehyde resins, or glycerol-phthalic acid resins. The adapter fitting may have any desired shape but preferably includes a cylindrical section 16 which has a circurnference substantially equal to the circumference of the sleeve when the sleeve is in its inflated condition. Cylindrical section 16 is preferably provided with an annular bead 17 at its inner edge to insure a tight fit between the open end of the sleeve, which fits over it, and the adapter fitting. The open end of sleeve 11 may be secured to the adapter tting by any means capable of providing a substantially airtight connection theres between. One satisfactory means comprises a clamp 18 which encircles the peripheral surface of section 16 and the end of sleeve 11 fitting over said peripheral surface. Clamp 18 includes screw means 19 adapted to tighten or loosen the clamp and to hold it in any position.

Adapter fitting 15 has a projection 20, preferably integral therewith, that extends from one face thereof forconnection to an air supply line (not shown). The outer section 21 of projection 20 is threaded, as indi-` cated at 22, so that it can lbe screwed into engagement with an air supply line. The inner section 23 of projection 2f) is shaped like a nut to provide a convenient surface to be engaged by a wrench, and facilitates tightening the connection between the diffuser tube and the air supply line.

An axial bore 24 extends through adapter fitting 15 and projection 20 to provide an air inlet for the flow of air from the supply line to the diffuser tube. The air inlet also provides a passageway through which air from the diffuser tube flows in the opposite direction to the atsteel or aluminum, or may be made of any suitable plastic material, such as, for example, fiber glass. The outer ends of legs 27 and 28 extend into recesses 3f) and 31 provided therefor in the face of adapter fitting 15 opposite the face from which projection 20 extends. The ends of legs 27 and 28 may be press fitted into recesses 30 and 31, or may be secured therein by pins, set screws, adhesive, or any other suitable securing means.

The width of skeletal frame member 25 is slightly less than the diameter of the sleeve when the sleeve is in its inflated condition. When sleeve 11 is in its inflated condition the difference between its diameter and the width of frame member 25 permits the frame member to hold sleeve 11 extended in substantially fixed position, relative to the adapter fitting, without any continuous surface contact between the frame member and the sleeve. The motion of the air passing through the interstices of the fabric of the sleeve, and of the liquid in which the diffuser tube is immersed, cause the sleeve, which is anchored only at the end secured to the adapter fitting, to float relative to the frame member. The floating movement of the sleeve prevents the frame member from blocking the flow of air through the interstices of any portion of the fabric of the sleeve.

When sleeve 11 is collapsed, legs 27 and 28 maintain the length ofthe sleeve, and also maintain the width of the sleeve along one diameter. The transverse perimeter of the sleeve is so dimensioned, relative to the length of a line extending along the outer surface of the skeletal frame member in its transverse direction, that the amount of slack in the sleeve transversely of the skeletal frame member, in the collapsed position of the sleeve, is equal to the perimeter of the rod of Which the skeletal frame member is formed. When the rapid deflation of the diffuser tube causes the walls of sleeve 11 to collapse, portions of the sleeve slap against each other. The amount of slack in the sleeve transversely of the frame member insures that the entire portion of the sleeve on one side of the frame member between legs 27 and 28 slaps against the corresponding portion of the sleeve on the opposite side of the frame member with enough force to dislodge the solid matter accumulated on the outer surface of the sleeve.

Frame member 25 may comprise two separate rods each having one end secured to the adapter fitting, or may have any desired skeletal conguration. The elongated U-shape is preferred because the curved intermediate section adds rigidity to the frame member and prevents twisting of the legs, thus maintaining them in parallel relationship. The parallel relationship of the legs of the frame member provides the maximum open space in which portions of the sleeve may slap against each other. If either leg of the frame member is twisted it will impair the slapping action of the sleeve. Another advantage of the elongated U-shape is that the fabric of sleeve 11 adjacent its closed end 13 is not subjected to as much wear by the movement of the fabric relative to the frame member when the sleeve is collapsed and reinflated, as it would be if the end of the frame member were of some other shape, as, for example, rectangular, instead of being rounded.

The embodiment of FIG. is identical to the embodiment shown in FIG. 1 except for a slight difference in the shape of the closed end of the porous sleeve. In FIG. 5, the closed end 13 of sleeve 11 is curved to conform more closely to the shape of intermediate section 29 of frame member 25.

Although we have described two embodiments of the invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details of structure may be modified or changed without departing from the spirit or scope of the invention. Accordingly, we do not desire to be restricted to the exact structure described.

We claim:

1. A difluser tube comprising a rigid inner skeletal frame member having an opening therein, a rigid adapter fitting secured to one end of said frame member, a flexible, collapsible, porous outer sleeve enclosing said skeletal frame member, said sleeve having one permanently closed end, means providing a substantially airtight connection between the other end of said sleeve and said adapter fitting, and an inlet for an aeriform body extending axially through said adapter fitting, the porosity of said sleeve causing air flowing through said inlet into said sleeve under pressure to flow into liquid in which said-diffuser tube is immersed, said sleeve having sufficient slack transversely of said skeletal frame member to cause substantially all of the portion of said sleeve overlying the opening in said skeletal frame member on one side of said frame member to slap against the corresponding portion of said sleeve on the opposite side of said skeletal frame member when said sleeve is deflated rapidly, to thereby dislodge solid matter accumulated on the outer `surface of said sleeve.

2. A diffuser tube comprising a rigid adapter fitting having two recesses in one end thereof, a rigid inner skeletal frame member comprising a U-shaped rod having its ends secured in said recesses, a flexible, collapsible, porous outer sleeve enclosing said skeletal frame member, said sleeve having one permanently closed end, means providing a substantially airtight connection between the other end of said sleeve and said adapter fitting, and an inlet for an aeriform body extending axially through said adapter fitting, the porosity of said sleeve causing air flowing thorugh said inlet into said sleeve under pressure to flow into liquid in which said diffuser tube is immersed, said sleeve having sufllcient slack transversely of said skeletal frame member to cause substantially all of the porti-on of said sleeve overlying the space between the legs of the U-shaped skeletal frame member on one side of said frame member to slap against the corresponding portion of said sleeve on the opposite side of said skeletal frame member when said sleeve is deflated rapidly, to thereby dislodge solid matter accumulated on the outer surface of said sleeve.

3. A diffuser tube comprising a rod having two substantially parallel legs and forming a rigid inner skeletal frame member, a rigid adapter fitting secured to one end -of said frame member, a flexible, collapsible, porous outer sleeve enclosing said skeletal frame member, said sleeve having one permanently closed end, means providing a substantially air-tight connection 'between the other end of said sleeve and said adapter fitting, and an inlet for an aeriform body extending axially through said adapter fitting, the porosity of said sleeve causing air flowing through said inlet into sai-d sleeve under pressure to flow into liquid in which said diffuser tube is immersed, said sleeve having slack transversely of said skeletal frame member equal in length to the perimeter of one of said parallel legs, said slack causing substantially all of the portion of said sleeve extending across the space between the two parallel legs of said skeletal frame member on one side of said frame member to slap against the corresponding portion of said sleeve on the opposite side of said skeletal frame member when said sleeve is deflated rapidly, to thereby dislodge solid matter accumulated on the outer surface of said sleeve.

4. A diffuser tube comprising a cylindrical rod having two substantially parallel legs connected at one end by a curved intermediate section, a rigid adapter fitting secured to the outer ends of the said legs, a flexible, collapsible, porous outer sleeve enclosing said rod, said sleeve having one permanently closed end, means providing a substantiallyair-tight connection between the other end of said sleeve and said adapter fitting, and an inlet for an aeriform body extending axially through said adapter fitting, the porosity -of said sleeve causing air flowing 8, 3 1 5 895 5 6 through said inlet into said sleeve under pressure to flow References Cited bythe Examiner int() liquid in Which Said diffuser lube S mIlleISed, Said UNITED STATES PATENTS sleeve having `slack transversely of said legs equal in length to the circumference of said rod, said slick causing gspgl substantially all `of the portion of said sleeve extending 5 3206178 9/1965 Lamb 261 122 across the space between said legs on one side of said legs to slap against the corresponding portion of said sleeve on M HENSON WOOD JR Pfl-mm3, Exmm-e the opposite side of said legs when said sleeve is deflated rapidly, to thereby dislodge solid matter accumulated on EVON C BLUNK Examine the outer surface of said sleeve. 10 V. M. WIGMAN, Assistant Examiner. 

1. A DIFFUSER TUBE COMPRISING A RIGID INNER SKELETAL FRAME MEMBER HAVING AN OPENING THEREIN, A RIGID ADAPTER FITTING SECURED TO ONE END OF SAID FRAME MEMBER, A FLEXIBLE, COLLAPSIBLE, POROUS OUTER SLEEVE ENCLOSING SAID SKELETAL FRAME MEMBER, SAID SLEEVE HAVING ONE PERMANENTLY CLOSED END, MEANS PROVIDING A SUBSTANTIALLY AIRTIGHT CONNECTION BETWEEN THE OTHER END OF SAID SLEEVE AND SAID ADAPTER FITTING, AND AN INLET FOR AN AERIFORM BODY EXTENDING AXIALLY THROUGH SAID ADAPTER FITTING, THE POROSITY OF SAID SLEEVE CAUSING AIR FLOWING THROUGH SAID INLET INTO SAID SLEEVE UNDER PRESSURE TO FLOW INTO LIQUID IN WHICH SAID DIFFUSER TUBE IS IMMERSED, SAID SLEEVE HAVING SUFFICIENT SLACK TRANSVERSELY OF SAID SKELETAL FRAME MEMBER TO CAUSE SUBSTANTIALLY ALL OF THE PORTION OF SAID SLEEVE OVERLYING THE OPENING IN SAID SKELETAL FRAME MEMBER ON ONE SIDE OF SAID FRAME MEMBER TO SLAP AGAINST THE CORRESPONDING PORTION OF SAID SLEEVE ON THE OPPOSITE SIDE OF SAID SKELETAL FRAME MEMBER WHEN SAID SLEEVE IS DEFLATED RAPIDLY, TO THEREBY DISLODGE SOLID MATTER ACCUMULATED ON THE OUTER SURFACE OF SAID SLEEVE. 